The present invention relates to an apparatus for photographically producing a relief surface on photopolymer plates so that the latter can be used in conventional letter-press printing operations. The photopolymer plates used in conjunction with the apparatus of the invention are developable with water, and are more fully described in the co-pending application of Sakuo Okai, Ser. No. 373,174, filed June 25, 1973, now U.S. Pat. No. 3,877,939, entitled "PHOTOPOLYMER PRINTING PLATES AND COATED RELIEF PRINTING PLATES".
A common process in the letter-press printing industry is the production of relief printing plates using photopolymer plates. A photopolymer plate is a laminated structure consisting of a thin coating of photo-sensitized plastic (a photopolymer surface) bonded to a metal or plastic base. The plate is exposed to the action of light through a negative photographic image (sometimes referred to hereinafter as a negative) causing the photosensitized coating to harden in those areas exposed to the light. The unexposed areas are then washed away by means of a suitable solution leaving a relief image. The plate is subsequently dried and postcured, whereupon it is ready for use in printing press operations. The use of such photopolymer plates is advantageous because of their inherent qualities which overcome many of the environmental problems associated with heavier, metal printing plates. However, the present production of each photopolymer plate requires several separate and sometimes isolated stages which are both expensive and time consuming. Moreover, the process generally requires considerable manpower. There is a need, therefore, to cut the expense, time, and manpower required for producing photopolymer printing plates. This need is especially apparent in newspaper plants, or large-scale printing concerns, which have to produce a substantial number of printing plates in a limited time.
It is accordingly an object of the present invention to provide an improved automatic apparatus for processing photopolymer plates requiring only the input of a photopolymer plate and a negative for the production of letter-press printing plates.
It is another object of this invention to provide an improved apparatus for continuously processing photopolymer printing plates.
It is a further object of this invention to provide an improved method for processing photopolymer printing plates.